The Zitterbewegung of the neutrino

The internal motion of the electron (i.e. Zitterbewegung) takes place in a hyperplane in the Minkowski space orthogonal to the four-vector p_u. For a four-component massless Dirac neutrino it takes place on a two-dimensional plane perpendicular to the three-momentum p, and for a two-component Weyl neutrino it takes place along a straight line perpendicular to p. The kinematical algebras of the compact internal quantum systems are so(5), so(4), and so(2), respectively.On leave from Department of Mathematics, University of Queensland, Australia